Even though there have been several patents issued for various devices or systems to raise or lower portions of a bed to improve comfort and change position of the occupant, most have not been widely accepted.
With an increasing need for care for those bed-ridden for either short or long duration, there is an increasing need for such occupants to perform as many functions as practicable for themselves. Further, a proper adjustable system would allow increased comfort for those many people who read or watch TV while in bed.
As yet we find no economical, easily used, and easily installed system for operation by the occupant for adjusting either or both the "head" portion and "leg" portion of a bed.
We have considered the following patents in this general area:
______________________________________ Patent Number Inventor Date ______________________________________ 2,769,182 E. J. Nunlist 11/06/56 3,392,723 C. E. Calvin 7/16/68 3,392,412 J. R. Aymar 7/16/68 3,606,623 J. R. Aymar 9/21/71 3,667,075 W. D. Ballard, Et Al. 6/06/72 3,978,530 J. G. Amarantos 9/07/76 4,287,620 H. C. Zur 9/08/81 4,309,783 M. A. Cammack 1/12/82 ______________________________________
None of these fill the needs as outlined below for this invention. This present invention fills the need for:
1. a low cost system to adjust portions of a bed;
2. a system easily operable by fingertip control of the occupant;
3. a system variably adjustable within safe limits to raise either or both "head" portion of the bed and "leg" portion of the bed;
4. a system that smoothly returns the bed to normal flat position;
5. a system intrinsically safe and easily sanitized; and
6. a system with easily replaceable and readily available parts.
The invention utilizes air bags below a hinged frame to raise the "head" portion of the bed and in the same manner utilizes a second set of air bags to raise the portion of the bed below the occupant's knees. The system has several unique features designed for ease of installation, ease and economy of manufacture, low cost transportation, ease of sanitation and economical part replacements.
The system is designed to be used with a normal bed and with variation in size may be used with a single bed, a double or standard bed, a queen size or a king sized bed.
Briefly, the system comprises:
1. a metallic frame which may be of aluminum pipes which may be approximately 1" in diameter; the frame is hinged on either side of the bed and on either side of a flat section which may be about one foot in length with the flat section made to be fastened to the bed frame;
2. a canvas cover for the total frame with approximately 11/2 inch thick polyurethane section or similar spongy material inside the canvas and inside the frame so that when the frame is slipped between the mattress and box springs that the mattress continues to be flat but approximately 11/2 inch higher from the floor;
3. a first pair of motor-blowers both to inflate and deflate the bags under the head portion of the bed and a second pair of motor-blowers similarly to deflate or inflate the bags under the "foot" or "leg" portion of the bed;
4. an electrical system with switches available to the occupant of the bed with necessary safeguards;
5. pressure and vacuum cut-offs to prevent over-pressure of the bags or burn out of the motors by operation against a closed suction.
The motor-blowers used were standard vacuum cleaner motors (which have blower built in). Vacuum cleaner motor-blowers are commonly used with the air blowing back over the motor. The unique deflation/inflation set up in this invention may be briefly described in an overall way in the following paragraphs.
A vacuum cleaner motor-blower fits very neatly into a piece of 41/2" PVC pipe and one motor-blower is slipped into the pipe with the motor facing in; a spring that fits loosely into the pipe is then slipped in and the second motor-blower is slipped in facing out so that we then have a spring separating the motor-blowers. We may activate one to blow air toward an inlet end of the assembly and, with this one deactivated the other one will pull air over the one that is deactivated so that by turning on one the air bags hooked to one end of this assembly will be inflated; by shutting off the one used to inflate the bags and activating the other the bags will be deflated.
One end of the assembly is closed with a cap containing an outlet fitting that fits closely into the pipe to hold the motor-blower while the other end is closed with a similar end cap that slips completely within the straight section of plastic pipe to hold the other motor-blower firmly against the spring separating the two motor-blowers. This end cap contains an opening that may fit against a diaphragm in a third end cap that fits within the straight piece of pipe. This third cap contains an air chamber behind the diaphragm and an equalizing line between this air chamber and the chamber formed where the spring holds the two motor-blowers apart. When the diaphragm in the third end cap is lifted up from the second end cap there is communication with the chamber formed over the top of the bell shaped second end cap. This chamber contains several holes which may be of 3/4" diameter leading to the outside air.
In operation, when the inflation motor-blower is activated a vacuum is pulled on the spring containing chamber; the equalizing line from this chamber to the chamber in the third end cap pulls a slight vacuum in this third cap chamber thereby pulling the flexible diaphragm away from the second cap opening so there is then a path to pull outside air over the inactive deflation motor-blower, through the spring chamber and thence to inflate the air bags hooked to the first end cap via flexible tubing. When inflation to a desired point is completed and motor-blowers deactivated the diaphragm becomes an efficient check valve to hold air in the bags.
In order to deflate the bags the inflation motor-blower is deactivated and the deflation motor-blower is activated. Because of the equalizing line between the spring chamber and third end cap the pressure on either side of the diaphragm is the same but as soon as the deflation motor-blower is activated the blower outlet pressure will raise the diaphragm providing an air path to the exterior.
This briefly describes a unique system that meets the objectives outlined. Total weight of the system may be less than 75 pounds so that it is easily portable and shippable. The mass produced vacuum cleaner motor-blowers are quite inexpensive and fit into inexpensive housings. In fact, the system used for deflation or inflation of the bags may be cheaper than an alternative system using only one motor-blower with a complex valving system. Various details have been left out of the above brief outline for clarity and brevity but would be easily supplied by one of normal skill in mechanical and electrical arts. A more complete explanation of a preferred embodiment will be found in the remaining specification and claims.
Many minor changes in details of this invention could be made but would still come within the spirit and purpose and fulfill objectives outlined. For example, the support frame could be of molded plastic with hinges molded in the frame; the motor-blower pair could be replaced with one motor-blower with microprocessor controlled valving or could be replaced with one blower for inflation and one for deflation with proper valving.